1. Field of the Invention
The present invention relates to an air conditioner, and particularly, to a multi-type air conditioner provided with a plurality of indoor units capable of cooling or heating each indoor space.
2. Description of the Background Art
In general, an air conditioner is an apparatus that can control the temperature, humidity, current and cleanness of the air for the purpose of making a pleasant indoor environment.
According to a configuration of units, the air conditioner is divided into an integration type air conditioner in which both an indoor unit and an outdoor unit are received in a single case, and a separation type air conditioner in which a compressor and a condenser are constructed as an outdoor unit and an evaporator is constructed as an indoor unit. Here, some of the air conditioners can selectively perform cooling and heating by switching a flow path of a refrigerant using a flow path switching valve.
Recently, a multi-type air conditioner having a plurality of indoor units for the purpose of cooling or heating each space is being increasingly used.
FIG. 1 is a schematic view of a conventional multi-type air conditioner. Referring to FIG. 1, the multi-type air conditioner 10 includes a plurality of indoor units 110, an outdoor unit 120 providing a compressed refrigerant to the indoor units 110, and a connection pipe 130 connecting the indoor units 110 with the outdoor unit 120.
The outdoor unit 120 is commonly installed on the top of a building, and each indoor unit 110 is installed in each room and on each floor. Thus, a height difference as high as H exists between the indoor units 110 and the outdoor unit 120, and a length (L) of the connection pipe 130 connecting the indoor unit 110 to the outdoor unit 120 becomes long, which makes return pressure of the liquefied refrigerant to the outdoor unit insufficient.
Thus, the liquefied refrigerant cannot return to the outdoor unit 120, a high pressure side, but is accumulated in the indoor units 110 and the connection pipe 130, a low pressure side. Particularly, such a phenomenon gets worse when the multi-type compressor is in a low-load operation mode where only some of the indoor units 110 are operated.
Consequently, refrigerant deficiency occurs at the high pressure side, which contributes to degrading reliability of cooling operation, and the liquefied refrigerant accumulated at the low pressure side may be introduced to a compressor (not shown) of the outdoor unit 120 and cause damage to the compressor.